Metal coil and method of forming the same



Dec. 9, 1941. QTT 2,265,246

METAL COIL AND METHOD OF FORMING THE SAME Filed July 7, 1939 PRIOR ART ZZ Patented Dec. 9, 1941 METAL COIL AND METHOD OF FORMING THE SALE John Ekern Ott, Lisle Township, Du Page County, Ill., assignor to Acme Steel Company, Chicago, 111., a corporation of Illinois Application July 7, 1939, Serial No. 283,132

4 Claims. (01. 242-78) This invention relates to improvements in metal coils and its purpose is to provide a novel coil of strip material or the like which may be used with advantage in stitching or stapling machines by which the parts of fiberboard boxes and other objects are secured together by metal stitches.

This stitching material, commonly known as stapling wire, is ordinarily formed as a narrow and comparatively thin steel strap and it has heretofore been supplied to the trade in the form of a continuous strip wound on a reel to form a number of concentric and radially superimposed cylinders in each of which the metal is coiled in the form of a helix. During the process of using this material in a stapling machine or the like, the coil is mounted on an axle about which it revolves and the surrounding wire fasteners which normally hold the convolutions of the coil from unwinding are removed, thus permitting the material to be unwound as it is used. It has been found that when the stapling wire is wound and used in the manner just described, great difliculty is encountered by reason of the fact that a considerable number of the outer convolutions of the coil unwind due to their own resilience and move laterally at various angles, becomin entangled with each other so that when a, pull is exerted on the free end of the stapling wire, the loops or convolutions nearest the free end enclose and bind the next adjacent convolutions, or are themselves partially enclosed and bound by adjacent convolutions so that it is dimcult or impossible to rotate the coil and unwind the stapling material therefrom:

The principal object of the present invention is to overcome the above mentioned difiiculties by providing a new form of coil of stapling wire, or the like, made up of superimposed. cylindrical layers, each comprising a helical arrangement of convolutions which, at the time of or preliminary to being wound in the coil, have been curled on radii less than those which they assume in the wound coil, so that each convolution tends to contract about the parts of the coil enclosed within it and retains itself in proper position as 'a part of a cylindrical layer without any auxiliary fastening means. Another object is to provide a newmethod of winding a coil of metallic material, such as stapling wire, steel strapping or the like, according to which the elongated metal member is progressively'curled by curling dies as it is wound on a core, so that it tends to assume a curvature of lesser radius than that which it occupies in the resulting coil and exerts a clamping action on one or more enclosed convolutions, thus preventing the accidental unwinding of the coil. A further object of the invention is to provide a coil of steel strip material made up of a plurality of cylindrical layers, each comprising a series of helically arranged convolutions placed edge to edge and being normally under contractile tension so that each convolution tends to wind itself up on the material enclosed within it. Other objects relate to various features of the improved method and to details of the construction of the coil which will appear more fully hereinafter.

The nature of the invention will be understood from the following specification taken with the accompanying drawing in which one embodiment is illustrated, In the drawing,

Figure 1 shows aside elevation of the improved metal coil of the present invention;

Fig. 2 shows an end elevation of the coil illustrated in Fig. 1; and

Fig. 3 is a view similar to that of Fig. 2 showing the type of coil heretofore used, after the wire fasteners have been removed, and illustrating the manner in which the outer convolutions of the coil become entangled with each other due to their tendency to unwind and move laterally.

The difficulty with the coils of stapling wire heretofore used will be further appreciated by reference'to, Fig. 3 of the drawing, in which there is shown a coil Ill made up of stapling wire I l which is in the form of a comparatively narrow flat steel strap. This strap is wound in a coil made up of a number of cylindrical layers, one of which is shown at l2. Each layer comprises a number of convolutions or loops I211.

' which are arranged edge to edge in helical fashion and, the fastening devices having been removed from the coil, the outer convolutions tend to unwind and to assume the straight form which they occupied before being wound in the coil so that a number of convolutions move laterally and overlap each other in irregular fashion ,as shown at i3, with the result that one or more convolutions adjacent the free end Ha are clamped by overlying adjacent convolutions in such a manner that the'.stapling material can not be unwound from tne coil and much time is lost in untangling the outer convolutions of such a coil during the operation of a stapling machine.

The improved coil M of the present invention is. shown in Figs. 1 and 2, where it is illustrated as being made up of stapling wire IS in the form of a flat flexible steel strap having some resilience, which is wound into a number of superwhen the coil is to be used, by untwisting the ends thereof.

During the process of forming the coil. shown in Figs. 1 and 2, the strip I5 is subjected to the Although one form of theimproved coil has been shown and described by way of illustration in connection with one form of an improved method of forming it, it will be understood that the coil may be formed in various ways and that the improvements of the present invention may be employed with various materials without departing from the scope of the appended claims.

I claim:

1. A metal coil comprising a plurality of radially superimposed layers of metallic material, each layer being formed as a continuous action of curling dies which curl it on a radius I less than that of the curvature which it assumes in the finished coil. This radius may be preferably slightly less than that of the core on which the coil is wound. The material of the strip [5 is somewhat resilient so that it tends to retain the curvature imparted to it by the curling operation and tends to contract about the parts of the coil enclosed within it. As shown in Fig. l, a portion 5b of a convolution which is partially removed from the coil assumes a curvature substantially less than that of the outer layer of the coil of which it forms a part. Similarly, all of the cohvolutions of the coil tend to contract and to assume curvatures having radii less than the radii which they occupy in the coil, so that the convolutions ofthe several layers l5 retain themselves accurately in place and in close contact with the enclosed layers of the coil, even after the fastening members I!) have been removed preliminary to using the stapling material in a stapling machine. With this arrangement; the loops or convolutions I6a of the coil may be successively withdrawn without interference by other convolutions of the coil.

series of connected helical windings of said material, the windings of each layer being formed to contract on those of the next inner layer.

2. A metal coil comprising a plurality of radially superimposed cylindrical layers of cylindrical metallic material, each layer being formed as a helical winding made up of a plurality of connected helical convolutions under contractile tension.

3. A metal coil of normally fiat strip material comprising a plurality of radially superimposed layers of said material, each layer being formed of a number of helically arranged convolutions of said haterial placed edge to edge, each of said convolutions being curled before winding on a radius less than that of its curvature in the coil.

4. The method of forming a metal coil which comprises the steps of curling an elongated metal strip and winding the strip in helical fashion on a core of greater radius than the radius of curvature imparted to the strip by the curling operation, and continuing the winding operation to form a plurality of superimposed helical layers each made up of connected helical convolutions placed edge to edge. I

JOHN EKERN OTT. 

